1. Technical Field of the Invention
The present invention is related to a singing voice synthesizing apparatus and, more particularly, to a singing voice synthesizing apparatus for synthesizing naturally sounding singing tones applied with suitable expression.
2. Related Art
Technologies are known in which a variety of parameters obtained by analyzing actually uttered voices are prepared and these parameters are combined to synthesize singing voices. One of these technologies is disclosed in Japanese Published Unexamined Patent Application No. 2002-268659 (refer to patent document 1).
Patent document 1 discloses the following technology. First, a database is prepared in which the parameters characterizing the formants of vocal elements are stored, and another database is also prepared in which template data for imparting time-sequential changes to these parameters are stored.
Also prepared beforehand are music score data having a vocal element track for specifying the vocal elements of lyrics in a time-sequential manner, a musical note track for specifying a song starting point and musical note transition points, a pitch track for specifying pitches of the vocal elements, a dynamics track for specifying a vocal intensity at each specified time, and an opening track for specifying a lip opening degree at each specified time.
In performance, the parameters are read from the tracks in the stored data and the above-mentioned template data are applied to these parameters to obtain the final parameters having minute changes for each time, thereby executing vocal synthesis of singing voice on the basis of these final parameters.
The types of the parameters and the templates to be prepared for the vocal synthesis are diverse. The preparation of these various types of parameters and templates allows the sophisticated synthesis of the singing voice which are diversified and resemble to natural human vocalization.
Patent document 1 is Japanese Published Unexamined Patent Application No. 2002-268659.
One type of the templates is desirably prepared for the synthesis of singing voices which are diverse and close to human vocalization, that is a template associated with expressions such as accent and portamento, for example. Variation pattern of formant and pitch of each vocal element depends on whether the expression is applied to the singing voice or not as well as the types of expression. Therefore, the synthesis of singing voices which are more diverse might be realized by preparing templates corresponding to different expressions and applying a template specified by a user to a desired part of the song.
However, the above-mentioned realization of the vocal synthesis with different expressions involves problems to be solved. For example, for the singing with an expression of the same type, the variation pattern of the formant and pitch of the vocal element depends on whether or not the music notes to which the expression is applied is preceded by contiguous musical notes. Thus, no proper and natural way of singing may be reproduced, unless different template data are applied selectably to one case where the music note to which the expression is applied is preceded by contiguous musical notes and another case where the music note is not preceded by contiguous musical notes.
It may be possible to prepare two different template data for one case where the music note to which the expression is applied is preceded by contiguous musical notes and another case where the music note is not preceded by contiguous musical notes, by analyzing each of the voices of attack and non-attack notes actually sung under these conditions. It should be noted that there do not exist so far such different templates for attack note and non-attack note. Even if such templates are created, however, this requires users who create song data to undertake a time and labor consuming task of making allocation of the two different template data to each vocal element on a case-by-case basis in order to impart the suitable and adequate expression to each vocal element.